arch/arm/mach-davinci/id.c

   1 /*
   2  * Davinci CPU identification code
   3  *
   4  * Copyright (C) 2006 Komal Shah <komal_shah802003@yahoo.com>
   5  *
   6  * Derived from OMAP1 CPU identification code.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/kernel.h>
  15 #include <linux/init.h>
  16 #include <linux/io.h>
  17
  18 #define JTAG_ID_BASE            0x01c40028
  19
  20 struct davinci_id {
  21         u8      variant;        /* JTAG ID bits 31:28 */
  22         u16     part_no;        /* JTAG ID bits 27:12 */
  23         u32     manufacturer;   /* JTAG ID bits 11:1 */
  24         u32     type;           /* Cpu id bits [31:8], cpu class bits [7:0] */
  25 };
  26
  27 /* Register values to detect the DaVinci version */
  28 static struct davinci_id davinci_ids[] __initdata = {
  29         {
  30                 /* DM6446 */
  31                 .part_no      = 0xb700,
  32                 .variant      = 0x0,
  33                 .manufacturer = 0x017,
  34                 .type         = 0x64460000,
  35         },
  36 };
  37
  38 /*
  39  * Get Device Part No. from JTAG ID register
  40  */
  41 static u16 __init davinci_get_part_no(void)
  42 {
  43         u32 dev_id, part_no;
  44
  45         dev_id = davinci_readl(JTAG_ID_BASE);
  46
  47         part_no = ((dev_id >> 12) & 0xffff);
  48
  49         return part_no;
  50 }
  51
  52 /*
  53  * Get Device Revision from JTAG ID register
  54  */
  55 static u8 __init davinci_get_variant(void)
  56 {
  57         u32 variant;
  58
  59         variant = davinci_readl(JTAG_ID_BASE);
  60
  61         variant = (variant >> 28) & 0xf;
  62
  63         return variant;
  64 }
  65
  66 void __init davinci_check_revision(void)
  67 {
  68         int i;
  69         u16 part_no;
  70         u8 variant;
  71
  72         part_no = davinci_get_part_no();
  73         variant = davinci_get_variant();
  74
  75         /* First check only the major version in a safe way */
  76         for (i = 0; i < ARRAY_SIZE(davinci_ids); i++) {
  77                 if (part_no == (davinci_ids[i].part_no)) {
  78                         system_rev = davinci_ids[i].type;
  79                         break;
  80                 }
  81         }
  82
  83         /* Check if we can find the dev revision */
  84         for (i = 0; i < ARRAY_SIZE(davinci_ids); i++) {
  85                 if (part_no == davinci_ids[i].part_no &&
  86                     variant == davinci_ids[i].variant) {
  87                         system_rev = davinci_ids[i].type;
  88                         break;
  89                 }
  90         }
  91
  92         printk("DaVinci DM%04x variant 0x%x\n", system_rev >> 16, variant);
  93 }